Grinding machine drive



i l 1% m April 11, 1950 Flled Aprll 27 1944 April 1, 1950 r. H. LJUNGGREN GRINDING MACHINE DRIVE Filed April 27, 1944 4 Sheets-Sheet 2 l g'mc or April 11, 1950 T. H. ILJUNGGREN GRINDING MACHINE DRIVE 4 Sheets-Sheet 3 Filed April 27, 1944 jaw/w ,w

A ril 11, 1950 Filed April 27, 1944 T. H. LJUNGGREN 2,503,674

GRINDING MACHINE DRIVE 7 4 Sheets-Sheet 4 V I. w W J, Z6 797$ Patented Apr. 11, 1950 GRINDING MACHINE DRIVE Thor H. Ljunggren, Charlestown, N. H., assignor to Bryant Chucking Grinder Company, Springfield, Vt., a corporation of Vermont Application April 27, 1944, Serial No. 532,944

2 Claims. 1

" This invention relates to grinding machines.

' One object of the invention is to provide an improved mounting for a movable carriage, which, in the case of a grinding machine, may carry either the work or the grinding wheel, this mounting facilitating traverse or feed, or both, 01' the grinding wheel with reference to the work.

Another object is to provide a mounting for the carriage of high sensitivity and rigidity. This is applicable both for traverse and for crosswise motion, the latter serving not only for relative feed between the tool and the work, but also when applied to grinding machines, for feeding the grinding wheel relative to a wheel dressing device when the wheel is out of grinding relation to the work and is in position where the work may be safely gaged, or removed and replaced with respect to the work holder.

A further object is to provide a mechanical drive mechanism for the traverse, which when applied to an internal grinder, will tend to prevent bell mouthing of the work.

A further object is to provide improved means for pre-setting the position of the path of motion of a carriage relative to its support.

For a more complete understanding of this invention, reference may be had to the accompanying drawings in which Figure 1 is a front elevation of the upper portion of a grinding machine embodying the invention.

Figure 2 is a top plan view of the "same.

Figure 3 is a fragmentary vertical sectional View on line 33 of Figure 2.

' Figure 4 is a detail sectional view on line 44 of Figure 3.

I Figure 5 is a detail sectional view on line 55 of Figure 4.

Figure 6 is a detail sectional view on line 6'B of Figure 3.

Figure 7 is a detail sectional view on line 'l1 of Figure 1.

Figure 8 is a detail sectional view on line 8-8 of Figure 7, but with a portion of the worm wheel broken away.

. Referring to the drawings, l indicates the bed 1 f the machine which has a platform 2 projecting upwardly therefrom at one end, and a support 3 narrower than the platform projecting upwardly spaced from the platform. Secured at opposite ends in the platfoorm 2 and the support 3, are a pair of parallel guide bars and 6, which, between the platform and the support overlie the bed I. These guide bars 5 and 6 slidably support a carriage 10, for this purpose the carriage having tubular bushings l l and I2 seated incylindrical 55 bores l3 and I4 therein. The interior bores of the bushings l2 are somewhat larger than the diameters of the bars 5 and 6 and in the space between them are placed sets of ball bearings. As shown, and as preferred, one of these bars, as the bar 5, has two such sets of ball bearings l5 and I6 and the other bar 6 has a single set of bearings IT. The balls of each of these sets of bearings are each of a diameter slightly greater than the normal space between the bars and the bushings So that when the sets of ball bearings are introduced between these parts they are under compression, being loaded by such compression to apredetermined amount. The sets of ball bearings are free to move longitudinally within limits. For example, the sets l5 and I6 surrounding the bar 5 have their longitudinal motions determined by end abutment rings and 2| and an intermediate abutment ring 22 at opposite ends of the bushings II. The set of ball bearings I! may have similar motion between corresponding abutment rings 23 at opposite ends of the bore I4. Suitable collapsible and expansible corrugated dust guards 25 may be posiitoned between the end plates 20 and 2| and the platform 2 and support 3 as shown best in Figure 6, thus to enclose the guide bar 5 against access of foreign matter to the outer face of the bar 5 which might find access to the ball bearings. Similarly the bar 8 is protected between the platform 2 and the support 3 by similar collapsible and expansible dust guards 26. The loaded sets of bearings accurately support the carriage without lost motion, but permit it to be moved axially freely and the three sets of ball bearings furnish a three-point support for the carriage which is thus in stable equilibrium atall times.

The traversing carriage Ill supports a feed carriage 30, and for this purpose the carriage I0 is provided with upwardly extending front and rear wall portions 3|, 32, within which are fixed opposite ends of a pair of supporting bars 35 and 36. Cross feed carriage is supported on these bars and 36 by the sets of pre-loaded ball bearings 31, 38 and 39. As preferred, one of the bars 35carries two of these sets of ball bearings as shown in Figure 3, while the other carries a single set- 39. As shown in Figure 3, the sets of ball bearings 31 and 38 may have limited axial motion between the end plates 40' and 4| and the intermediate ring 42 similarly to the mountings of the sets of bearings l5 and It on the-bar 5. The single set of ball bearings 39 may have similar limited motion between abutment rings similar to those described-for the bearing IT. This provides a slow.

three-point support for the cross feed carriage 30 similar to the mounting of the longitudinal feed carriage II] with respect to the bed I. Expansible and collapsible dust guards 44 may fill the spaces between the end plates 49 and M and the wall portions 3I and 32, and similar dust guards 45 may be employed extending between the end plates 42 and 43 and the wall members 3| and 32.

Between the bars 35 and 36 a cross feed shaft 50 may be positioned, this being operatively connected by any suitable means, as is well known in the art, for producing forward and backward motions of the carriage 3B. This feed shaft 50 may also be covered between the sides of the cross feed carriage 30 and the walls 3! and 32 of the carriage ID, as by expansibleand collapsible dust guards 52 and 53 similar to the guards which protect the sets of guide bars 35 and 33. and and 8.

The carriage mounting is not claimed herein but forms subject matter of a divisional application Serial No. 729,843, filed February 20, 194?,

f or Carriage mounting.

- As shown the carriage 3D has secured thereto 4 produced by the rocking of a member 8I' journaled on a bushing 82 on the shaft I8 and arranged to be clutched to the shaft I8 as desired, but in order that the position of the zone of traversing motion may be regulated in accordance with the specific relations of the grinding Wheel and the work in any particular set-up, means are provided by which the angular relationship between the member SI and the shaft I8 may be adjusted as desired. For this purpose a member 85 is rockably supported on a bushing 83 surrounding the shaft I8 outwardly of the forward face of the bed I. This member 85,

' as best shown in Figures 3 and 4, has journaled similar expansible pulley 69 on the armature shaft I9 of a motor II also carried on the platform 2.

S ecial means are provided, in accordance with this invention, for moving the carriage In so as to effect a relative traverse between the grinding wheel and the work, this means having for a particular object to time the motion of the carriage Ill so that adjacent the ends of the traverse it is in contact with the work during a time not substantially greater than its time of contact with intermediate portions of the length of the work. For example, if the carriage is traversed in harmonic motion as by a uniformly rotating crank and a pitman, the intermediate portion of the traverse is relatively rapid while the end portions of the traverse are relatively Where such a variable speed reciprocation is employed, the end portions of the work are in contact with the grinding wheel longer than the intermediate portions and thus are ground more, resulting in the end diameter portions of the ground work being of greater diameter than the intermediate portions, this being called bell mouthing. In accordance with the present invention a simple mechanism is provided by which the rate of motion of the'traverse is much more nearly uniform than is the harmonic motion --previously mentioned. As shown the traversin mechanism includes a rack bar (see Figure 3) iii secured longitudinally in a groove I6 in the lower face of the carriage I!) and between the harsli and 3, and with which meshes a gear I1 secured to a shaft l8'suitably journaled in hearing bushin'gsIS, in a portion 8!! of the machine bed I, it being evident'that by turning the shaft I8 the gear 11 may be rotated, which through its engagement with the teeth of the rack bar I5. produces the desired axial motion of the .grinding'wheel. Such motion of the shaft- I8 is therein transverse to the axis of the shaft 18,

an adjusting shaft 89 provided with a worm 90 meshing, with a worm wheel 9I secured to the forward end 'of the shaft I8 as by screws 92. This member has a portion 93 provided with a socket 94 within which rides a spring pressed pin 95. This pin 95, as shown in Figure 5, has a beveled outer end 96 which rides against a similarly beveled abutment 9'! having a shank portion 98 seated in a perforation 99 in an arm H10 projecting from a casing IUI which straddles the member 8'5 and is rockably supported on either side thereof on the shaft 89. This casing member Ill! has a hand wheel I02 integral therewith, the casing 50! forming a hub for this wheel, access being had to the gear 9! therein through an opening normally closed by a cover I05 secured over the outerface of the hand wheel as by screws I93. To the back face of this hub or casing IIII is secured a latch member II'Il provided with a tapered-nose III projecting rearwardly therefrom, and which may be engaged in a slot H2 through an arm H3 projecting outwardly from the rocker member 8!. When the latch member is in engagement in the slot N2 the hand wheel is locked to the rocker member 3 I the upper portion of the hand wheel being tilted rearwardly as shown by dotted lines in Figure 3. When the wheel is inthis position, the casing member and hand wheel being locked to the rocker 8|. the hand wheel, through the worm and worm wheel, is locked to the forward extremity of the shaft 18, so that when the member 8| is rocked,'the shaft I3 is correspondingly rocked. The upper portion of the hand wheel may be moved into the full line position of Figure 3, however, removing the latch III from engagement with the slot H2 and thus disconnectingthe hand Wheel from the rock member 8!. In this position'of the parts, the angular relationship between the shaft I8 and t e element 85 may be adjusted as desired by turning the worm shaft 89, and when this worm shaft is adjusted to the desired position, the hand wheel may be tilted backwardly and again latched to the rock member 8|, thus operatively connecting the rock member 8| to the shaft E8 in a new position of angular relationship.'-' By this means the angular relationship between the rock member 8| and the gear TI may be adjusted so as to adjust the limits of traverse motion of the carriage Ill, and thus the position of its zone of traverse, as the rock mem-' ber Si is rocked between definite limits. I Rocking of the member 8! is effected by rotatio'n of the crank pin I20 (see Figures 1 and?) which is adjustable in a T slot IZI from and toward its center of rotation. The crank disk I22 and the crank arm I 20 are connected to a crank pin I23 extending from an arm I24 ,of the rock member BI as by means of a pitman I 25 journaled at oppositeends on the pins I23 and I20;

Rotation of the crank pin I20, the throw of which is less than that of the arm I24, acting through the pitman I25, oscillates the rock member 8| and thereby produces traversing motion of the carriage I0. As this motion with a constant speed of rotation of the crank pin I20 would produce an undesirably fast traverse carriage motion in the intermediate portion of its stroke, and an undesirably slow traverse motion toward the ends of its path, provision is made in accordance with this invention for driving the crank pin I20 at a variable speed, so arranged as to slow the carriage traverse speed intermediate its ends and to speed up the traverse speed adjacent to the ends. Such mechanism is shown in Figures 7 and 8. The crank disk I22 is secured to a shaft I30 to which is keyed an elliptical gear I3I meshin with asimilar gear I32 keyed to a shaft I33. Also keyed to this shaft is a worm Wheel I34 with which meshes a worm 35 on a drive shaft I36. The shafts I30 and I33 with their corresponding gears are housed within a casing I40 mounted within the bed I and outwardly of this casing the worm shaft I36 has secured thereto a belt pulley I31 over which passes a drive belt I38 leading from any suitable source of power.

The elliptical gears I3I and I32 are so arranged angularly with respect to their shafts that the small diameter portion of the gear I32 engages the large diameter portion of the gear I3I, thus driving the shaft I30 at a slow rate of speed, when the carriage I is in its mid position of traverse, thus producing a slower traverse than would otherwise be produced, while when the carriage I0 approaches its limits of motion, the large diameter portion of the gear I32 is driving the small diameter portion of the gear I30, thus speeding up the angular motion of the crank pin I20 and correspondingly speeding up the traverse motion of the carriage I 0.

The inner traverse limit of the carriage I0 may beadjusted as desired, a micrometer stop being shown at I50 for this purpose on Figure 1, and the feed position, laterally, of the carriage 30 may be determined by micrometer feed mechanism indicated generally at II in Figures 1 and 2. These, however, form no portion of the present invention.

From the foregoing description of an embodiment of this invention, it should be evident to those skilled in the art that various changes and modifications might be made without departing from the spirit or scope of this invention.

I claim:

1. In combination, a carriage, a drive shaft, connections from said shaft for producing linear motion of said carriage in opposite directions, a driving member journaled on said shaft, means for turning said member angularly in opposite directions through a predetermined angular extent, a second member journaled on said shaft,

a worm shaft journaled in said second member, a worm wheel fixed to said drive shaft and engaging said worm, a locking element rockable on said worm shaft, and parts on said locking element and driving member interengaging when said locking element is in one angular position about said worm shaft to lock said members together and through said worm and worm gear to said drive shaft in a definite relation, said lookin element when out of locking angular relation permitting angular adjustment between said drive shaft and second member by rotation of said worm shaft, said worm shaft having a toolreceiving portion.

2. In combination, a carriage, a drive shaft, connections from said shaft for producing linear motion of said carriage in opposite directions, a driving member journaled on said shaft, means for turning said member angularly in opposite directions through a predetermined angular extent, a second member journaled on said drive shaft, a worm shaft journaled in said second member, a worm wheel fixed to said drive shaft and engaging said worm, a locking element rockable on said worm shaft, and parts on said locking element and driving member interengaging when said locking element is in one angular position about said worm shaft to lock said members together and through said worm and worm gear to said drive shaft in a definite relation, said locking element when out of locking angular relation permitting angular adjustment between said drive shaft and second member by rotation of said worm shaft, said worm shaft having a tool-receiving portion, said locking element being formed as a casing enclosing said worm shaft and worm wheel and being provided with a hand wheel portion.

THOR H. LJUNGGREN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

